I’ve got a father-in-law who is very inconsistent with his moods and body cues. For one day he will laugh at any joke you tell him, and the next he will shout at you for a perceived slight from hours ago and then give you the cold shoulder. He’s made me cry from his attitude shifts.

My wife can’t get through to him without a fight happening.
His wife (my mother-in-law) is calm and understandable, but is a pushover for him.

Have any of you navigated hard relations with an in-law? Do you have any tips?